“Parents and educators deserve honest, accurate information about how well their students are performing, and the extent to which they have a solid foundation for their continued learning,” said Michael Cohen, president of Achieve. “Tests are not the only source of this information, but they are certainly an important one. We don’t do our students any favors if we don’t level with them when test results come back.”

According to the report, more than half of states report a difference of 30 percentage points or more between their own proficiency results and those provided by NAEP. Georgia, for example, had one of the largest discrepancies for the 2013-14 year, reporting proficiency levels for fourth-grade reading and math that were 60 and 53 percentage points higher, respectively, than NAEP reported.

Essentially, what this means is that many states are sugar-coating test results, even test results for tests of their own creation and implementation. For this reason, Achieve urges states, educators, families, and students to make use of the NAEP results, at least as a cross-reference for test results. Achieve also urges continued use of national standards, such as Common Core aligned testing to ensure greater accountability.

By contrast, some states, which the report deems “truth tellers,” are accurately reporting student achievement. The report notes that New York, for example, actually boasts proficiency requirements on its state tests that are more rigorous than NAEP according to the 2013-14 data. It was also the only state to report a smaller percentage of proficiency than NAEP for both fourth-grade reading and eighth-grade math. For that, New York earned the highest rank on Achieve’s “Top Truth Tellers” list.

Proficient vs. Prepared asserts that while the “misleading” deficiencies are a problem, many states are working to correct the “honesty gap” by introducing more challenging and rigorous curriculum and aligned assessments that can better measure a students’ college and career readiness. Kentucky had some of the nation’s largest gaps in proficiency before adopting the Common Core State Standards in 2010. The state narrowed a 32-percentage-point differential to 15 between 2011 and 2014, the report notes.

“Leaders in many states have already recognized the need to administer more rigorous tests that will provide more honest and accurate information. Unfortunately, in some states there is already political pressure to abandon their new assessments and go back to using less rigorous tests,” said Cohen. “This report shows us that we can’t go back to the way we’ve always done it.”